Pixelitor

Pure Data

Pure Data is a visual programming language. It is possible to create and manipulate video, graphics, images in realtime with extensive possibilities for interactivity with audio & external sensors.

Sculptgl

SculptGL is a web sculpting application.

traGtor

for converting any type of video, picture, audio.

Valentina

Valentina is an open source pattern drafting software tool.

Ibniz

IBNIZ is a virtual machine designed for extremely compact low-level audiovisual programs.

Avidemux

Avidemux is a simple software for editing videos.

Fist

Fist is à generator for ASCII image.

Bitmap Generator

This program will allow you to generate bitmap fonts from TrueType fonts.

SuperCollider

Supercollider is an environment and programming language for real-time audio synthesis and algorithmic composition.

Freeplane

Freeplane is a free and open source software application for bulding mind maps.

piskel

A simple web-based tool for Spriting and Pixel art.

Triangle (It is not a freeware, until proved otherwise)

for generated Delaunay triangulations

Stellarium

Stellarium is a software of real time astronomy.

Metaflop

Metaflop is an easy to use web application for modulating your own fonts.

Dita

Dia is a program to draw structured diagrams.

FreeCAD

FreeCAD is a 3D CAD/CAE parametric modeling application. It is primarily made for mechanical design, but also serves all other uses where you need to model 3D objects with precision and control over modeling history.

Krita

Krita is a open source software for digital painting. It is made by artists that want to see affordable art tools for everyone.

Make 8bit art

Inkscape

TILED

You can edit maps for video games or you can also use it to create pattern and experiment with typography.

Blender

Blender is the free and open source 3D creation suite. It supports the entirety of the 3D pipeline—modeling, rigging, animation, simulation, rendering, compositing and motion tracking, even video editing and game creation.

G.Projector

G.Projector is a Java application which allows you to explore a large collection ofglobal map projections and optionally project an an input GIF, JPG or PNG equirectangular map image.